The present invention relates to a novel gel comprising a mixture of carboxylic acid, amine, and solvent; a paste, in particular soft solder paste, in which the metallic component is dispersed as a powder in the gel; and the application of soft solder pastes on UBM's (Under Bump Metallization); and the use of these soft solder pastes for power-modules, die-attach, chip-on-board, system-in-package (SiP), wafer-bumping, or SMT (Surface Mounted Technology), particularly coated circuits.
German Patent DE 841 097 discloses soldering agents, in which the amine is condensed with the carboxylic acid to ureides. According to DE 841 097, it is taken into account that carboxylic acids and amines are present in mixtures. However, it is referenced that they enter into chemical compounds with each other and form, e.g., ureides.
German Patent DE 41 19 012 describes a soft solder paste, which can be washed out with water, comprising a soft solder powder, a bonding agent-flux agent mixture made of water-soluble salts of fatty amines with carboxylic acid and solvent.